Mechanical cardio pulmonary resuscitation device having a contact member

A mechanical cardiopulmonary resuscitation (CPR) device, comprising:

• a piston;
• a driving component configured to extend the piston toward a patient's torso and retract the piston away from the patient's torso;
• a controller configured to perform mechanical CPR by controlling the driving component to at least compress the patient's torso by extending the piston from a reference position to a compression depth and retracting the piston from the compression depth to the reference position, wherein the reference position is the position from which the depth of CPR compressions are measured;
• and
• a pressure pad attached to the end of the piston, the pressure pad having a pressure pad contact surface area and a material disposed on the pressure pad contact surface area, the material configured to attach to a target area on the patient's torso, the material including a semi-adhesive material that has low adhesiveness when the controller controls the driving component to compress the patient's torso between 1 and 60 times per minute and high adhesiveness when the controller controls the driving component to compress the patient's torso more than 60 times per minute.